Selective inertia lumber marker



Feb. 9, 1965 R. c. M RAE 3,163,353

SELECTIVE INERTIA LUMBER MARKER Filed Feb. 20. 1961 2 Sheets-Sheet 1Roberf'CMcHae INVEN TOR.

ATH'y.

1965 R. c. MGRAE 3,168,63

SELECTIVE INERTIA LUMBER MARKER Filed Feb. 20. 1961 2 Sheets-Sheet 2 g i3 i Rober r CMcPae INVENTOR.

:1 4, 944% 9; 94 9 94 92 BY 7w United States Patent f 3,168,863SELECTIVE INERTIA LUMBER MARKER Robert C. McRae, 3421 N. 35th, Tacoma,Wash. Filed Feb. 20, 1961, Ser. No. 90,369 4 Claims. (Cl. 101-43) Thisinvention relates to apparatus for marking pieces of lumber and otherarticles as they move past a marking station.

In the lumber industry it is usual practice to grade lumber according tospecified standards and to mark each piece with the grade mark. Themarking can be done most expeditiously and to best advantage as thelumber leaves the mill on an off-bearing conveyor moving rapidly at arate of, for example, 100 lineal feet per minute.

Since it is not practical to slow down or stop the conveyor to permiteach piece to be marked, it is no possible to use conventional markersincluding reciprocating printing heads mounted on a stationary frame ata marking station. The motion of the printing heads of such markers ischaracterized by a hesitation or dwell at the end of each stroke whenthe head is in contact with the moving piece. As a result, the mark isblurred.

It is the object of the present invention to provide apparatus formarking moving articles such as pieces of lumber without blurring themark, even though the pieces are traveling rapidly.

It is another important object of the present invention to providelumber marking apparatus which operates efficiently on lumber which iswarped, crooked, or misaligned on the conveyor.

Still another object of this invention is the provision of lumbermarking apparatus adapted for application of commercial grade marks tosorted lumber pieces.

Still another object of this invention is the provision of articlemarking apparatus suited for application to the selective marking ofindividual articles on a full scale production basis.

The manner in which the foregoing objects are accomplished will beapparent from a consideration of the accompanying specification andclaims considered together with the drawings, wherein:

FIGS. 1 and 2 are side and front elevations, respectively, of the hereindescribed marking apparatus in advanced position;

FIG. 3 is a view in side elevation, similar to FIG. 1, but with theapparatus in retracted position;

FIG. 4 is a schematic diagram illustrating the manner in which theherein described marking apparatus is applied to the selected marking ofarticles, e.g. pieces of lumber as they are conveyed on a commercialproduction line; and

FIG. 5 is a schematic wiring diagram of the apparatus of FIG. 4.

Generaly stated, the method of marking articles described hereincomprises moving the articles past the marking station at which arelocated inertia type marking means. The marking means is advancedrapidly toward the selected moving article, the advancing motion beingabruptly arrested shortly before contact. The inertia of the markingmeans then continues its advancement into momentary marking contact withthe article after which it is retracted to its starting position, readyfor another cycle of operation.

It is a particular feature of the invention that a plurality of markersof the class described may be installed at the marking station,associated with a plurality of electric switches or other actuatingdevices stationed at intervals along the conveyor on which the articlesare conveyed past the marking station. The articles are sorted so thateach will energize a selected one of the 3,168,861 Patented Feb. 9, 196.

actuating devices. This, in turn, actuates the associate marker. By thismeans pieces of lumber may be grade and marked with the grade mark at arate sufficient t accommodate the entire production of a mill at thenorm: production rate.

Considering the foregoing in greater detail and wit particular referenceto the drawings:

As shown in FIGS. 1, 2 and 3, the marking apparatu of my invention ismounted at a marking station wit reference to a conveying line 10 onwhich articles to b marked are conveyed continuously past the station.Th apparatus is mounted on support means such as a leve arm 12 the innerend of which is pivoted through pi: 14 to a frame member 16. The outerportion of leve arm 12 is angled downwardly and supports a markin headindicated generally at 20. This element of th apparatus includes ahousing 22 in which is mounted to vertical sliding movement an inertiatype plunger 24 The upper end of plunger 24 extends upwardly beyon theplane of housing 22 and is threaded to accommodat a nut 26. Compressionspring 28 is interposed betwee. nut 26 and the top surface of housing22.

A printing or marking die 39 is fixed to the lowe end of plunger 28 andbears on its printing surface th selected lumber grade mark or othermarking indiciz Arcuate guide plates 32 are present, one on each sid ofthe housing, being formed integrally therewith in th illustrated form ofthe invention.

Drive means are provided for reciprocating arm 12 and marking head 20carried thereby, toward and awa from the work on conveyor 10. Stop meansare assC ciated with the drive means for arresting its advancin movementabruptly as required to impart inertia move ment to plunger 24.

In the form of the invention shown in the drawings the drive and stopmeans are combined in a single, fluid operated cylinder, specificallypneumatic cylinder 34, th upper end of which is pivoted by means of pin36 to a extension of frame member 16 and the piston rod 0 which ispivoted by means of pin 38 to bearings carrie by the angled outer end oflever arm 12. Cylinder 3 is of a conventional type and is supplied withair unde pressure through lines 40. It is controlled electricall bymeans of solenoid 41. It completes a cycle of opera tion, advancing andretracting its piston, upon applica tion of but a momentary electricalimpulse to the sole noid. In the at rest position, the cylinder isretracted When a momentary electrical impulse reaches the sole noidthrough electric wires 42, the piston extends rapidl and slams against acushion of trapped air. This op erates a pilot valve, not shown, whichimmediatel reverses the cylinder and returns it to its rest position.

Inking means are associated with the marking heal for supplying ink tothe working face of die 30. To thi end a bracket 44 extends outwardlyfrom the frame mem ber 16. It mounts bearings 46 in which a shaft 48 ijournaled. Shaft 48 supports a pair of parallel arms 50 52, which mountbetween them a pair of rollers 54, 56 Roller 54 is an ink-containingreservoir roller; roller 56 in peripheral contact therewith, anapplicator roll. Th margins of roll 56 ride on guides: 32.

A spring 58 is mounted between a first post 60 extend ing outwardly fromframe 16 and a second post 62 ex tending outwardly from an upwardextension of arm 50 Accordingly applicating roll 56 wipes back and fortlacross the face of die 30 with each advancement and re traction of thewiping head.

The space between die face 30 and the surface of ar ticles on conveyor10 is sufficient to accommodate irregu larities which may be present inthe articles to be marked For example, when stamping lumber pieces withgrad marks, the space may be as much as from one-half t1 hree-quartersinch in order to accommodate pieces of umber which are warped or whichhave surface irreguarities.

It is a particular feature of the present invention that narking unitssuch as that described above may be emplayed in combination with eachother to apply selected grade marks or other identifying indicia toselected categories of articles. Such a system is illustrated in FIGS. 1and 5, the arrangement being one contemplated for use n sorting lumberon the grading chain of a sawmill, and for applying the correspondinggrade mark to each piece.

Thus there is illustrated the grading chain 66 on which are conveyedpieces of lumber 68, 70, 72, 74. Piece 74 purposely is illustrated asbeing slightly askew, a condi- ;ion which necessarily occurs from timeto time in normal nill practice.

Paralleling chain 66 and adjacent thereto is a table 76 Craving spacedlongitudinal lines 80, 82, 84, 86 bearing, respectively, the numerals 1,2, 3 and 4 to indicate the corresponding lumber grades. Substantiallyaligned with .ines 80, 82, 84, 86, at the outfeed end of table 76 are aplurality of laterally spaced sensing elements, electric switches 90,92, 94, 96. These are in an electric circuit with a plurality oflaterally spaced marking units 100, [02, 104, 106. Each of these bears agrade mark corresponding to lumber grades 1, 2, 3, and 4.

Also included in the electric circuit is a contact switch 98 locateddownstream from the sensing switches.

The circuit including the switches and marking units is illustrated inFIG. 5. It will be seen that switches 92, 94 and 96 are single pole,double-throw switches, while switches 90, 98 are single pole,single-throw switches. Each of these switches, with the exception ofswitch 98, upon operation closes a circuit including one of markingunits 100, 102, 104, 106. In so doing, each of double throw switches 92,94, 96 excludes from the circuit all of the marking units except the oneit is desired to energize.

Operation The operation of the herein described marking apparatus is asfollows: Each marking unit, as illustrated in FIGS. 1, 2 and 3, isenergized by an electrical impulse passing through solenoid 41. Thiscauses the automatic extension of cylinder 34 until its piston slamsagainst a pocket of trapped air, as explained above, thereby abruptlyarresting its forward motion and instituting its retrac tion to itsstarting position.

When the cylinder reaches its position of maximum advancement, i.e. theposition of FIGS. 1 and 2, its abrupt reversal of motion causes inertiaplunger 24, and marking die 30 which it carries, to continue theiradvancement until the die comes into momentary marking contact with thework carried on conveying line 10. The duration of contact is for sobrief an interval, that there is no blurring whatsoever of the stampedmark, even though the work is moving at a rapid rate.

As the printing head advances, it automatically inks the marking die.This is accomplished by the wiping action of inking roller 56, suppliedby reservoir roller 54, across the face of die 30 as the die moves fromthe retracted position of FIG. 3, to the advanced position of FIG. 1 andback to the retracted position of FIG. 3, there being two passes of theinking roller across the die face for each stroke of the latter. Thisinsures effective inking.

Also to be noted is the fact that the inertia movement of the markeraccommodates inadvertent irregularities in the height of the articlesbeing marked. This is of particular importance when marking lumber,since the lumber frequently is warped or characterized by surfacedefects which affects its height.

When the marking units are used in a group, as in FIGS. 4 and 5, lumberpieces 68, 70, 72, 74 are sorted according to grade by an operatorstanding at table 76. This is accomplished by adjusting the position ofthe lumher pieces to positions gauged by lines 80, 82, 84, 86,corresponding to lumber grades 1, 2, 3 and 4. Thus, as illustrated,board 68 has been positioned so that its end registers with line 82,board 70, with line 80, board 72, with line 84, and askew board 74 withline 86.

As the boards travel successively beneath marking units 100, 102, 104,106, they pass contemporaneously beneath actuating or sensing units 90,92, 94, 96. In the case of board 74, a grade 4 piece, all of the latterswitches will be closed. By reference to FIG. 5 it will be seen that asa consequence, marking unit 106 is energized while units 100, 102, 104are inactivated. Accordingly, when the board closes switch 98, which isin series with the sensing switches, marking unit 106 alone will beenergized and will stamp the board with the grade form mark.

Similarly, when board 72 reaches the sensing switches it will operateswitches 90, 92, 94 only. As a consequence, marking unit 104, the grade3 unit, will be actuated while units 100, 102 will be thrown out of thecircuit and unit 106 will remain uneffected in its rest position. in asimilar manner, board 70 will actuate grade 1 marking unit only, andboard 68, grade 2 marking unit 102 only.

If switch 98 were to be omitted, a board which is misaligned, or acurved board, might actuate one of switches 90, 92, 94, 96 before theothers, thereby causing an instantaneous operation of the associatedmarking unit. This possibility is eliminated by locating switch 98downstream from the sensing switches.

It is to be understood that the form of my invention herein shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of my invention or thescope of the subjoined claims. Thus there may be substituted for thespring restrained inertia plunger 24, alternate but equivalent mechanismsuch as spring hinges, resilient whip arms, and the like.

Having thus described my invention, I claim:

1. Apparatus for marking moving articles which comprises a lever arm,means for pivotally mounting the inner end of the lever arm to astationary support, drive means coupled to the lever arm intermediateits ends for reciprocating it between advanced and retracted positions,stop means associated with the drive means for abruptly arresting itsadvancing motion, a spring-retained inertia plunger mounted on the outerend of the arm, a printing die mounted on the plunger for momentaryprinting contact with articles toward which it is advanced by the drivemeans, and inking means positioned for movement by the lever arm forinking the printing die on each stroke thereof.

2. The apparatus of claim 1 wherein the printing die is provided witharcuate guides and wherein the inking means comprises inking rollers ona spring-actuated lever arm positioned for movement along the guides,traversing the printing die face with each stroke of the die.

3. Apparatus for marking articles passing a marking station, theapparatus comprising: conveying means for conveying the articles pastthe station, a plurality of laterally spaced indicator means spacedlaterally with respect to the conveying means for identifying the manualposition of articles laterally of the conveying means according to type,an electric circuit, a plurality of contact electric switches in seriesin the electric circuit spaced laterally with respect to the conveyingmeans and corresponding in number and alignment with the indicatormeans, another contact electric switch located a spaced distancedownstream from the first mentioned contact electric switches and inseries circuit relationship with them, each contact electric switchbeing disposed for engagement and actuation by the articles, and aplurality of electrically controlled markers in the electric circuit,each marker being actuated selectively by one of the contact electricswitches, provided said another contact electric switch is closed,thereby marking the article positioned with reference to the indicatormeans.

4. Apparatus for marking moving articles on a surface disposedsubstantially parallel to the line of movement, the apparatus comprisinga lever arm, means for pivotally mounting the inner end of the lever armto a stationary support, drive means coupled to the lever armintermediate its ends for reciprocating its outer end between advancedand retracted positions, inertia plunger means mounted on the outer endof the lever arm for movement between advanced and retracted positionssubstantially corresponding to the direction of movement of the leverarm, resilient means interengaging the lever arm and plunger and urgingthe latter toward said retracted position, a printing die mounted on theplunger, and stop means associated with the drive means for abruptlyarresting the advancing motion of the lever arm short of the surface ofthe article to be marked, whereby to cause the inertia plunger to beadvanced against the resistance of the resilient means to bring theprinting die into momentary printing contact with the surface of thearticle.

References Qited in the file of this patent UNITED STATES PATENTS1,706,632 Onstad Mar. 26, 1929 1,925,236 Doyle et al. Sept. 5, 19332,541,800 Whittaker Feb. 13, 1951 2,559,455 Meyer July 3, 1951 2,603,150Klug July 15, 1952 2,646,746 Muller July 28, 1953 2,913,978 Lane Nov.24, 1959 2,952,204 Sherman Sept. 13, 1960

1. APPARATUS FOR MARKING MOVING ARTICLES WHICH COMPRISES A LEVER ARM,MEANS FOR PIVOTALLY MOUNTING THE INNER END OF THE LEVER ARM TO ASTATIONARY SUPPORT, DRIVE MEANS COUPLED TO THE LEVER ARM INTERMEDIATEITS ENDS FOR RECIPROCATING IT BETWEEN ADVANCED AND RETRACTED POSITIONS,STOP MEANS ASSOCIATED WITH THE DRIVE MEANS FOR ABRUPTLY ARRESTING ITSADVANCING MOTION, A SPRING-RETAINED INERTIA PLUNGER MOUNTED ON THE OUTEREND OF THE ARM, A PRINTING DIE MOUNTED ON THE PLUNGER FOR MOMENTARYPRINTING CONTACT WITH ARTICLES TOWARD WHICH IT IS ADVANCED BY THE DRIVEMEANS, AND LINKING MEANS POSITIONED FOR MOVEMENT BY THE LEVER ARM FORINKING THE PRINTING DIE ON EACH STROKE THEREOF.